Abstract
The Author investigated the occurrence of naturally antibiotic- resistant strains of Streptococcus equi. A lot of 31 strains was isolated from nostrils or suppured lymph glands of race horses, along a survey of strangles in Jockey Club Paulistano — Sao Paulo — Brasil. Between them, there were 31 animals with active strangles, 93 clinically healed and 101 healthy adult horses. All strains identified as Streptococcus equi were tested by the disc-plate method against penicillin, streptomycin, aureomycin, terramycin and chloromycetin in variable concentrations of the antibiotics. Seven out of all showed resistance against 0,5 unit of penicillin and two others against 1 meg of streptomycin. Repeating the test, now by the dilution test tube method, the same strains did not confirm those fastness properties. The results suggest two possibilities: a) the disc-plate method was not so accured as the dilution test tube method; b) the strains were really resistant when recently isolated but along subcultures they have lost their drug-fastness. As a matter of fact, this condition was confirmed in another investigation, when resistant strains were obtained by successive transfers in broth with penicillin. The actual data suggest that naturally antibiotic-resistant strains of Streptococcus equi do not occur, exception not so clear being made for some strains in relation to penicillin.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Revista da Faculdade de Medicina Veterinária, Universidade de São Paulo
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.